[llvm] [SPIRV] Fix compile abort on a switch case value shared with a module constant (PR #223548)

[Manuel Carrasco via llvm-commits]

mgcarrasco wrote:

Is it possible that the CI failure is due to invalid SPV and that bug is independent of the crash that is being fixed?

If so, maybe the test could be simplified such that the crash is still reproduced, and does not trigger the validity one. The new validity bug can be addressed later on a different PR (assuming they are unrelated).

https://github.com/llvm/llvm-project/pull/223548